Full time (permanent contract)

Full remote, hybrid or on site (Grenoble, France)

The XCP-ng team develops and maintains critical components of our virtualization platform, including the Xen hypervisor, Linux kernel, Network stack (Open vSwitch) and the Storage stack (SMAPI). Our primary focus is security, performance, and maintaining excellent reliability. We are creating a dedicated Performance Team responsible for tracking and identifying bottlenecks across the stack, such as: Grant mechanism in Xen, Tapdisk/blkif components for storage, Network PV drivers (netfront and netback), Open vSwitch (OVS), NUMA effects and optimizations, specific CPU instructions etc. We are looking for an experienced low-level developer with expertise in system performance tooling and best practices. Familiarity with benchmarking tools is essential, including:

• fio (storage benchmarking)
• iperf (network benchmarking)
• perf (performance analysis)
• General tracing and benchmarking tools

Networking knowledge (LLDP, VLANs, QinQ, tunneling, etc.) is a plus.

As part of the Performance Team, you will collaborate with experienced Xen developers at Vates and the Xen community, improve Xen, QEMU, Linux kernel (Dom0), and guest OS components (PV drivers), generate clear traces, benchmarks, and performance improvements for server workloads and finally work on key areas of Xen and Linux to optimize performance.

• BS in Computer Science or related discipline, or equivalent work experience
• Several years of experience working on the Linux Kernel or similar operating systems
• Strong skills in C and Python programming
• Familiarity with performance tooling and benchmarking frameworks

Vates is a French software company specializing in Open Source and virtualization with a deep commitment to open, collaborative development. Our main projects, Xen Orchestra and XCP-ng, span the full virtualization stack—from the hypervisor (Xen) and virtualization platform (XCP-ng) to management and VM backups (Xen Orchestra). Our team works across multiple countries, fully embracing remote work with transparent workflows and accessible communication channels. At Vates, we are driven by a strong, people-first culture that values benevolence, inclusivity, and a horizontal structure. Every member is empowered to contribute ideas, make decisions, and grow with the company. Our open-source model is core to everything we do, not just in our code, which is available on GitHub and GitLab, but in our collaborative approach with the community. We believe in "upstream first," dedicating our expertise and resources to support and advance foundational projects like Xen, and helping contributors of all levels join us on this journey.